Means for severing well casings and the like in place in the well



Feb. 17, 1948. L. F. DEFENBAUGH MEANS/FOR SEVERING WELL CASINGS'AND THE LIKE IN PLACE IN THE WELL Filed Sept. 14, 1944 2 Sheets-Sheet l IN VEN TOR.

n W M F LZOyd BY @L 2 Sheets-Sheet 2 "1.. F. DEFENBAUGH Filed Sept. 14, 1944 INVEN TOR.

ENN W N Feb. 17, 1948.

MEANS FOR SEVERING WELL CASINGS AND THE LIKE IN PLACE IN THE WELL WJ. a w m w F W b L Patented Feb. 17, 1948 4 eans For: suvenmdwnnn causes at rnnrms Peace IN THE WELL Lcya r. Defenbaugh,' Oklahoma City, 0kla.; Application September 14, 1944, Serial No. 554,108

6 Claims.

This'invention relates to the severing of struc- "well, or an" exploratory'well, 1 particularly when "using rotary drills, it frequently happens that the drill stem becomes stuck in'the well bore and cannot be withdrawn. The'present practice, in

such cases, isto shoot the drill stem ofi with ex- 'plosives', 'or"to clit it off with mechanical tools, after which the drill and the portion of the stem attached thereto are recovered by known means.

Both oi'these operations are time consuming, err-- f pensive and extremely hazardous. the well casing has been set, during drilling "of a well or after completionthereof, it may become necessary" to remove a section of the casing.

Also, after tureat that 'area'thereby severing the structure. Further objects and advantages-of my invention will appear from the detail description.

In the drawings:

Figure 1 is a fragmentary vertical sectional view of a well bore", shown rather-diagrammatically, and of a drill stem passing throug'hfthe well bore, with severing means embodying my invention positioned within the drill stem;

Figure 2 is a view slmilar'to Figure 1 but after severing of the drill 'stem has been completed and the'remains of the severing means" have been 'removed from the drill stem;

' Figure 3 is'afr'agmentaryvertical sectional view of a well with the casing therein, showing severing m'ean's embodying my-invention positioned within the casingat the area thereof where it is desired to sever thec'asingi' and I Figure "4 is a view similar to'Figure 3 after The casing is cemented or grouted in the weir-'20 the severing operation has been completed and bore and cannot be removed therefrom, so thatit *is necessary to work within the well bore at whatever depth the section;- of the casing is to be removed. The present practice is to remove the the remaining parts of the severing means have desired section by mechamgal'm hi h strata, indicated more or less diagrammatically 'uuiresa considerable amount'of equipment and "takes considerableltime, which is objectionable for obvious reasons. severing-bf the well casing at -the desired depthmay be accomplished 'by'the use of explosives, or shooting," but that shat- ;te'rsthe casing and is highlydetrimental to normal operations of thewell, for which reasons shootingis used as a last resort where attempts to sever'the casing and remove a section thereof I by mechanical "means have proved fruitless.

My invention'is' directed to avoidance of the abovejreferredfto' objections to the present prac- "tice'. Tothat end, Ip'rovide means whereby a at the proper area thereof sufficient to fuss or dedrlll stem or valve casi'ngor analogous structure limy that area of the stem. The severing means, may be 'severe'd at a desired area thereof with err-1 ipedition" and facility by the application of intense f heat at that area'. More specifically, 'I provide means forfsup'portmg at the desired area within :the tubular structure 5. mass or body of-an exo-, thermic mixture and for closing'the bore of the -structure' at the bottom of such mixture 'so' as sub'stantially to prevent leakage of the molten maf-terial'resuItingfromthe exothermic chemical reaction, 'and means for initiating chemical reac- Itim re; whereby when chemical re-" action of; the mixture takes place the resultant molten material is maintained in contact with the interlor' suriace of the structure at the desired ar'ea thereoi'and by the intense heat of the chemby oppositely directed cross hatching. A drill stem '6 passes downwardly within the bore 5, this stein including a joint-I having a bore 8 which is reduced in diameter or restricted relative to the bore of the adjacent lengths of tubing of the stem. :It may be assumed, for purposes of description, that the drill (not shown) 'from which the stem extends, is a rotary drill and has become stuck in the well bore necessitating severing of the drill stem a short distance above the Joint 1 thereof.

In order to effect severing of the drill stem; I provide meanswhereby heat may be generated indicated in its entirety" by reference number 10, is in the form of'acontainer comprising a, cylindric'al body ll formed of an elastic fabric, or of any other suitable -elastic material, having conreactionof such mixture destroys the strucsiderable elasticity and adequate mechanical strength. At'its lower end body H receives a 'disc'shaped' head'ltfittin'g-therein and having :a depending cylindrical flange 13 to the lower end of which issecured. conveniently by being formed integral therewith;-a.- cone shaped guide member =-.I 4'. The lower end of body I I. is secured in a suit- :able manner, "conveniently by riveting, to fian e 13, the latter being provided with diametrically --opposite lengthwise "slots 15;, Anchoring -mem- -bers 16; in the form of levers which are crossed anclipivcted. together at 11,- on a supporting tab or retracted position.

or bracket l8 at the under face of head I2, extending downward within flange l3 in alignment with the slots l5 thereof. Each of the levers IB is provided, at its lower end,'with an arcuate serrated member l8 adapted for gripping engagement with the interior surface of the drill stem, when the members l6 are projected through the slots I5 into operating position. The levers it have upwardly extending arms 20 projectin through a slot 21 in head l2, the upper portion 22 of each arm 20 being twisted at right angles so as to provide a seat for one end of a compression spring 23 of considerablestrength, confined.

between the upper portions 22 of arms 241'? and urging the latter apart so as to force the members l6 outward through slots l5; Theend portionsof spring 23 receive centering studs-24 carried by upper portions 22 of arms 20, and a strain wire 25 is secured to the upper portions or elements 22' or arms 20 adjacent the upper ends thereof, this wire being of adequate strength normally to hold arms :20 against movement away horn-each other under the influence r spring 23 and thereby hold the anchor members It in their inoperative Preferably, superposed slotted plates 26-fit about-arms 2-0 at the upper face of head 12 and substantially closeslot 2|. for .a purpose which will appear presently.

The body i I, closed at itsiower end by head -l-2, provides a container which receives in its lower portion a mass orbodyof la-suitablearefiraetory material 21, such as clay, which is in a loose condition. The container further receivesamass or body 28 of anexothermic mixture,.such as thermit. The'depth of the refractory 21 is such that strain wire 25isdisposedradjacent theupper face of the refractory, preferably aasl i ghtsdlstance thereabove and in the':bottom= portion of the body of thermit 21. Asecuring plate fll oisteel or any other suitable' material, is -:seenred z-to =.1:-he

upper end of the'body-H of the-econtainer'ateach side thereof, theseplatesrbeing-idiametricallyaopiposite each other and receiving the endipontions of a bail 3|. A supporting cable 32-, which may be either a steel cable or'aiwrope; is suitably asecured to bail 3| and carries an electric lcabl-e 33, which passes through'thetopof bO'dy l ro-f'zsthe container and extends downward therein to an ignition device 3'5 located in-th'e lower portion or the body of thermit :28. of any suitable type, conveniently-beinggln the form of a block or body 36 carrying aresistor wire 31 to the ends of whichare-connectedsu'itably insulated terminal posts 138, .to which the wires of cable-33 are connected. "It will'sbe zunders't'ood that when the electric circuit, or the resistor 31 is closed, 'this wire is heatedbto incandescence or *sufflcient 'tb' assure initiation of the chemical reaction 'of' the thermit. @It wiiiiabe noted that the resistor 31 1s disposed in pron'imity to the strain wire '25, which'is fusible or iheat destructible-so that upon "initiation of' the ichemical reaction of the thermit 28 tlrestrain--wirei25 is immediately destroyed, releasing-the; rrns: -20. 'Itmay be'assumed'thatthe drilisteni as one or more joints above-joint '1 which, 'like-tl'leilatter =jo'in't, 'pres'ent relatively-restricted bores. {The diameter of flange l3 'is-somewhat les most restricted bore in the -drill stem tonjunctionWith *the inverted 'irust'oconi'calg idemember I 4, and the elasticity o'f"-body il'=l= {Of ithe container, assures that the container cahn-readily be lowered to any desired position within {the drill stem. In that connection, it willijbe":understood that the load supported byhead'di ismp- This device may' :be Y

preciable so that when the device In is supported by cable 32 the elastic body II is under lengthwise tension and its maximum diameter is sub stantially the same as the diameter of head [2, plus the thickness of the wall of body ll. Further, body ll being elastic and readily flexible may be distorted to suificient extent to assureready passage of the heating device through re-, strictions inthe drill stem; the bail 31, being or arcuate shape and possessingfiappreciable resiliency, being also capable of distortion for that purpose.

When the device ID has been properly posit'ioned e within the drill stem, chemical reaction of the thermit mixture 28 is initiatediby means ref-"the 'i-g-niter 35. When that occurs, the strain wire 25 is destroyed and compression spring 23, which is of considerable strength, projects the members l6 outward of slots i5 so as to cause the serrated elements l8 thereof to grip the inner surface of the drill :stem, anchoring the-device l0 therein against downward movement, The-operator-at the well top then slacks-thesupponting cable 32 so that thedevice. -10 islthenesupported by the anchoring means and body lof-ithe con-- tainer' is relievedof lengthwise tension. In v:that connection, the operator can readily edetermine by thefeelof cable 32-whether or not-the device isproperly anchored within the-drill-steml ,In the outward movement ofthe anchoring. .members i6, and the'-'accompanying;=outward movement of arms 20,, elements 2-2 of ,these arms i-force a portion of the refractory or clay 21- outwardof :head l2 toward the periphery thereof, so that upon relieving the lengthwise tension of ibodyil-l the latter bulges outwardabout head l2 :SOJES to close the space between. the headz-and :the drill stem. This outward movement of. the refractory is augmented bythe superposed mass-of thermit,

the lower portion of which :now is in liquid condition -due;.to the chemical reaction; which has been initiated, andrthe :mblten mater-ial resulting firom such reaction which may tend to-flow between the drill stem and head 1-2 is restrained :by the clay or refractory and on cooling provides-a further seal about head,.l-2. In that manner :the body or mass of molten material-resulting from the chemical reaction of the thermit-is-suppor-ized -upon the bed of clay-or refractory, the :latter'inconjunction with the plates 26 and "the portions of arms 20 within the body of =clay or refractory serving to prevent any; objectionable leakage at the molten-material through: slot .2l of head d2.

Since :the body H of the container is elastic, as above-noted, when it is relieved "of lengthwise tension it contracts and displaces the refractory and the thermit mixtureoutwardrradially.icausi-ing bulging of the clay containingportions lot i abody' 'll into contact with the surrounding wall ofthe drill stem and ;alsocausing--bul ln M the thermit containing portion of thGwbOdYE'riD-tfl contact with the surrounding -wall :01- the. drill stem, or substantially so. Thet body' H zofz'the container is heat destructible, as, will be-lunderz-s'tood from the above, and is quickly destroyed by-"the heat generated by the chemical .=reaction of the thermit, which-generates ;he ate-iat -a temperature of approximately 3000* C." 'ilfhexmolten mass resulting from the chemical reaction-ofithe thermit mixture is thus brought :into direct ,contact with the drill -stemand:quickly -destroys-fthe :area thereof at which the device Ml :is located, :thus severing the stem, the, upper portion-mt whichaisthen separated ;from (the-lower cportion bythe-resultant-sap, asishown;inrFigurera...

; v severed upperjportion .of the stem is then withdrawn from the well bore and the remaining portion of the stem and the'drill may be recovered by a fishing operation in a known manner. In Figures'sand 4 I have shown a section of awell with a casing 40 secured therein by cement or concrete 4! in a known manner. Assuming-thatit is desired to remove a section of the casing 40, the heating device 10, such as that above described, is suitably j positioned within casing ",after which the chemical reaction of the thermit mixture is initiated, the device It is anchored in position within the casing, and the latter and the surrounding cement or grouting 4| are destroyed by the heat of the chemical reaction of the thermit mixture, leaving a gap 42 in the well casing and the cement or grouting, as shown in Figure 4. After that has been done, the desired section of the casing 40, above or below the gap 42, or between two properly spaced gaps produced in the same manner as the gap 42, is removed in a known manner.

'While I have shown, by way of example, one form of means for anchoring the heating device within the drill stem or the well casing, any other suitable means may be provided for that M purpose. Likewise, the heating device may be .nositioned within the tubular structure to be sev- :-:ered in any suitable manner, or by any suitable means other than the lowering cable illustrated by way of example. While I have referred to the body of the container as being heat destructible, it is not essential to my invention that it be completely destroyed, it suflicing if the body is of such characteras to permit of severing the tubular structure by the heat generated by the exothermic mixture or material of the heating device.

The body of the container should be elastic for use in drill stems and other structures having restricted bores spaced apart therein, but that is not essential in all cases and for use in well caslugs and other structures of like character the container body may .be nonelastic if desired. Also, any suitable means other than the ignition device, shown by way of example only, may be provided for initiating chemical reaction of the exothermic mixture, within the broader aspects of my invention.

As above indicated, and as will be understood by those familiar with the drilling and operation of wells, changes in details may be resorted to both with respect to the heating device of my invention and the method of my invention, and I- intend to include all such variations, as fall; within the scope of the appended claims, in this application in which the preferred form only of my invention has been disclosed.

I claim:

1. In means for severing tubular structures by heat,f,a container comprising a body formed of flexible heat destructible material adapted to be disposed in desired position within a tubular structure to be severed, a body of loose refractory material in the lower portion of said container, a body of an exothermic mixture in said container overlying said body of refractory material, means for initiating chemical reaction of said mixture, and initially inoperative means for anchoring said container in position within the tubular structure,

' said anchoring means comprising heat destruc tible means maintaining said anchoring means inoperative and being rendered operative responsive to initiation of chemical reaction of said mixture and resultant destruction of said heat I destructible means.

2: In means for severing tubular structuresby heat,"a container adapted to be disposed in desiredposition within a tubular structure to be severed, said container comprising a, body formed of a, heat destructible material and a head at the lower end thereof, a body of refractory material in the lower portion of said container overlying said head, a body of an exothermic mixture in said container overlying said body of refractory material, means for initiating chemical reaction of said mixture at a, point adjacent the bottom thereof, and means for anchoring said container in position within the tubular structure comprising initially retracted members and means urging said members outward for engagement with the tubular structure and heat destructible means adjacent the point of initiation of reaction of said mixture initially holding said members in retracted position, said heat destructible means upon destruction thereof releasing said members for movement outwardly into anchoring engagement with said tubular structure.

3. In means for severing tubular structures by heat, a container adapted to be disposed in desired position within a tubular structure to be severed, said container comprising a body formed of a heat destructible material and a head at the lower end thereof, a body of refractory material in the lower portion of said container overlying said head, a. body of an exothermic mixture in said container overlying said body of refractory material, means for initiating chemical reaction of said mixture at a point adjacent the bottom thereof, anchoring members pivoted on said head for movement outward thereof into engagement with the tubular structure, means urging said members outward, and heat destructible means adjacent the point of initiation of reaction of said mixture initially holding said members retracted.

4. In means for severing tubular structures by heat, a container adapted to be disposed in desired position within a tubular structure to be severed, said container comprising a heat destructible body and a head at the lower end thereof, a body of refractory material in the lower portion of said container, a body of an exothermic mixture in said container overlying said body of refractory material, means for initiating chemical reaction of said mixture at a point adjacent the bottom thereof, said head having a slotted depending cylindrical flange and a guide cone at the lower end thereof, locking levers pivoted on said head movable outward through the slots of said flange, said levers having arms extending upward through said head, spring means connecting said arms urging said levers outward, and a fusible strain wire connecting said arms restraining outward movement of said levers and disposed adjacent the point of initiation of reaction of said mixture.

5. In means for severing tubular structures by heat, an elastic heat destructible container adapted to be disposed in desired position within a tubular structure, a body of loose refractory material and a body of an exothermic mixture in said container disposed in superposed relation with said material underlying said mixture, and means for initiating chemical reaction of said mixture.

6. In means for severing tubular structures by heat, a heat destructible container adapted to be disposed in desired position within the tubular structure to be severed, a body of an exothermic mixture in said container, initially inoperative anchoring means carried by said container rendened operative responsive .to initiatien; of; chemical reaction; of. said' exothermic: m xture and eflectivewhenopemtive fori anchoringsaidmonr Nnm ei tamer in position within said; tubular structure. and; means for. initiating; chemical. reaction. of ,5

said mixture.

L. DEEENBAUGH.

REFERENCESCITED.

r The following: references are of 'recozrd in.- the file of" this patent:

Name 7; 12am, Waitz ,.Mar. 12, 1,918 Mims j Apnzil, 1926 Saner Dec;.,1 0,.,1935

Anderson ---i Opt. 20,. 1936 Van Meter V Jam. 17, 19, 9

Boynton ..'I. ."Apn. 6, 194:3 

